Due to development of technology and consumers' requirement, handheld electronic devices nowadays provide multi-functions. Take a smart phone for example, instead of providing only basic features, advanced functions such as internet, e-mail, photographing, and video recording functions are always provided as well. Consequently, power consumption of each component in the handheld electronic device should be strictly managed in order to extend standby duration of the electronic device.
Basically, current electronic devices are equipped with solid state drive (hereinafter, SSD) components to save data such as files, programs, pictures, videos and so forth. Such solid state drives are thus named as embedded multi-media card (hereinafter, eMMC).
SSD components use NAND flash memory. As flash memory is non-volatile, data saved to the SSD components are reserved even if the electronic device is shut down.
FIG. 1 is a schematic diagram illustrating connections between a host and a solid state drive in a conventional electronic device. In the electronic device 100, the solid state drive 110 is electrically connected to the host 112 through a bus 120, for receiving a read command or a write command generated by the host 112. The host 112 may be a control processing unit (hereinafter, CPU), and the bus 120 may be a USB bus, an IEEE 1394 bus, or SATA bus etc.
Furthermore, the solid state drive 110 includes a control unit 101, a cache memory 103, and a flash memory 105. Being utilized by the control unit 101, the bus 120 transmits commands and data between the control unit 101 and the host 112. The control unit 101 accesses data stored in the flash memory 105 according to the commands sent from the host 112. Besides, the cache memory 103 is electrically connected to the control unit 101 and used as a temporary buffer for temporarily storing the write data from the host 112, and the read data required by the host 112.
The solid state drive 110 is one of the numerous components in the electronic device. Thus, an important purpose of the present invention is to efficiently manage power consumption of the solid state drive 110 while providing efficient operation between the solid state drive 110 and the host 112 and securing safety of the stored data.